“A lot of people think, ‘I don’t like the terms of the will’ or ‘That’s not what Mom or Dad told me, so I’m going to challenge the will.’ But it’s not so simple,” said Patricia Davidson, a Massachusetts-based attorney who helps families resolve issues involving wills, trusts, and real estate. To contest a will, Davidson said, you must have evidence to back up your claims, not just a hunch, suspicion, or sense of unfairness. Contesting a will isn’t cheap, and requires a solid argument. Vague feelings of unfairness won’t work before a judge.

Alternate name: Challenging a will

For example, say your mother remarried in the last months of life to her in-home nurse, who didn’t let you visit your mom. Upon her death, you read her will and find that it leaves her entire estate, including her home, jewelry, and cash, to her nurse and spouse. Because you believe you should have been a beneficiary, you might consider contesting the will.

How Contesting a Will Works

The grounds and process for contesting a will depend on your state’s laws, but the concepts are similar. When the will is filed in probate court, interested parties receive notice. Those parties must object within the time period provided by the jurisdiction’s laws. The court then determines if the will is valid and determines heirs, beneficiaries, worth, and assets. After a parent dies, mixed emotions manifest themselves in complicated ways, Davidson said. “Will contests are often rooted in misunderstanding, guilt, jealousy, and simmering sibling rivalry.”

Who Can Contest a Will?

First, you need to determine whether you can legally contest a will. Typically, the only people who can legally challenge a will are those who would have otherwise benefited—for example, someone named in a prior will or who, under state law, would have received assets if no will existed. For example, in Oklahoma, if a will doesn’t name a child or grandchild, they may be able to argue that they were forgotten—not intentionally excluded—and may have rights to a portion of the estate. Children of the deceased person are the most common objectors, Davidson said. Will contests are also common when “the decedent had no kids and extended family members litigate their alleged claims to the estate,” she said.

Reasons To Contest a Will

“Most will contests arise out of complicated family dynamics, and it can be a challenge for a lawyer to balance emotional and psychological issues with legal reality,” said Davidson. “Often in these cases, parties are not just pursuing assets, but challenging a whole power dynamic, particularly if one sibling is designated the personal representative or executor.” According to Davidson, the underlying motivation to contest a will may include:

Greed or envy Lack of understanding about how estate plans work Anger at other beneficiaries (such as siblings) Contradictions between what the decedent said and what the will says

But to be successful, you must have legal grounds to contest a will based on state law and provide evidence for your claim. For example, you might need to prove:

The testator lacked the intent or capacity to draft the willThe testator was under undue influence or duress from a third partyFraud or mistakes occurredPrior wills weren’t correctly revokedOther circumstances that led to the will being void

In Ricciardi’s practice in Florida, most cases of contested wills involve “undue influence,” often after a new beau appears late in a person’s life and a will is amended. He said that lack of capacity is more challenging to prove in Florida; even if the deceased was incapacitated or experienced dementia, they might have had a “lucid moment” while creating the will.

Next Steps: Evaluate Your Case With a Lawyer

“Consulting with a lawyer is always the right thing to do,” Davidson said. “A lawyer can explain circumstances where someone can and cannot try to challenge a will, the process for doing so when appropriate, how long the process could take, the cost, and potential alternatives to shepherd resolutions, short of going to trial.” “You can’t do it yourself,” warned Ricciardi about contesting a will. “These are usually extensive cases, and turning over a will is not easy.” Once you speak with a lawyer, a discovery process begins, during which the lawyer gathers evidence supporting your claim. Depositions will be taken. Each side will provide records and proof of its position. The next steps depend on your case, the parties and legal teams involved, and your state. Most of Davidson’s cases in Massachusetts don’t go to trial, as she usually tries to reach a compromise. Most cases ultimately settle. “Mediation is a great tool to help lawyers help their clients compromise, stop the bleeding of legal fees, and mitigate the risk of court,” Davidson said. “Mediation gives parties more control in a resolution.” If the case proceeds to trial, a judge hears the evidence and makes a decision.

What Does It Cost To Contest a Will?

In general, prepare to spend at least $5,000 to $10,000 to contest a will, Ricciardi said, with many costs stemming from extensive research and behind-the-scenes work. A complaint is rarely settled in just a few weeks. Some attorneys may work on contingency—and aren’t paid unless you are—but that would depend on having an extremely strong case. “With a personal injury from a car accident, you know you’ll probably get something, but contesting a will isn’t that [kind of] situation,” Ricciardi said. Your success in challenging a will depends on the facts and the strength of your case, Ricciardi said. “Your chances aren’t 50-50, as the burden is on you to prove your case, and your star witness is dead.” Want to read more content like this? Sign up for The Balance’s newsletter for daily insights, analysis, and financial tips, all delivered straight to your inbox every morning!